Avast interfering with steam. Games taking forever to download.

I had some sort of virus for a while that took over my McAfee program and wouldn't allow me to turn scanning on. Having no antivirus protection I acquired some viruses, I assume and yesterday my computer crashed. I restarted it multiple times and I couldn't open up any program without the computer completely freezing and internet explorer opening random websites. I decided to restore my computer to factory settings today and installed the free trial of avast premier. It was working fine until I started to re download my games on steam which were downloading incredibly slow. Avast has its own firewall so I thought I should turn windows firewall off. When I tried to do this it said McAfee was controlling windows firewall. When I tried to delete McAfee nothing would happen. I guess my dell computer came preloaded with McAfee. Could McAfee be interfering with avasts firewall causing the slow download rate on steam? Any help will be greatly appreciated as I have no idea what to do.

Welcome to OCF

Time to get a little more specific. What type of system are you discussing? Laptop? Desktop?

Beyond that, can you get the computer booted?

Desktop, I successfully uninstalled McAfee but, steam still seems to be downloading very slowly. The computer boots fine.

What version of windows are you running?

You can get a second opinion on virus problems, even a third, for free. Download and install Malwarebytes, https://www.malwarebytes.org/antimalware/; also drop MS Security Essentials on the OS, http://windows.microsoft.com/en-us/windows/security-essentials-download, run them both, make sure the MS firewall is turned on, then check out your startup folder for too many programs/applications all starting up and hogging resources.

Post back your impressions.

To add to Robert's recommendations:
- Remove Avast before installing Security Essentials.
- Run Malwarebytes from Safe Mode over and over until the scan comes up clean.

Im running windows 7. Ill follow your advice and post my results.

When I did the restore I didnt do if far enough back so my computer was reinfected. When I tried to start it today it wouldn't even boot so I reinstalled windows 7 using a usb drive.I succesfully installed it, but when I logged in I noticed it looked completely different. The bottom bar was much larger then it was before, The screen looks zoomed in and the shortcuts are all much bigger, and when I go into control panel or computer the windows take up the entire screen and cant be made smaller, only minimized. Could I have downloaded a wrong version of windows 7? I also failed to realize that I would need to install all new drivers and was very confused when I couldn't connect to the internet. I tried to install the drivers by looking them up with the network cards ven id but it says they aren't supported on my device. Sorry for the long wall of text but I have no idea what im doing.

I'm assuming you're on Ethernet?

I was on my old laptop when I made that post. I downloaded the Ethernet drivers and was able to get an internet connection. I did the windows update and windows looks fine now. Did windows download all the necessary drivers or will I need to manually download some?

Check device manager to see what drivers are/aren't installed.
I would go to your motherboard manufacturer's site to get the newest drivers though. Same for the GPU.

Also, where did you download Windows from?